Exception from HRESULT 0x80072EE7

try
{
    if (!string.IsNullOrWhiteSpace(txtEmailId.Text))
    {
        string _userId = txtEmailId.Text;
        if (Regex.IsMatch(_userId, @"^(?("")("".+?(?<!\\)""@)|(([0-9a-z]((\.(?!\.))|[-!#\$%&'\*\+/=\?\^`\{\}\|~\w])*)(?<=[0-9a-z])@))" +
    @"(?(\[)(\[(\d{1,3}\.){3}\d{1,3}\])|(([0-9a-z][-\w]*[0-9a-z]*\.)+[a-z0-9][\-a-z0-9]{0,22}[a-z0-9]))$", RegexOptions.IgnoreCase))
        {
            if (!string.IsNullOrWhiteSpace(txtPassword.Password))
            {
                string _password = txtPassword.Password;
                requestUri = objHttpHelper.login_url;
                requestUri = string.Format(requestUri, _userId, _password);
                uri = new Uri(requestUri);
                response = await httpClient.GetAsync(uri);
                string strResponse = await response.Content.ReadAsStringAsync();

                LoginDetails loginDetails = JsonConvert.DeserializeObject<logindetails>(strResponse);
                           

                IList<error> err = loginDetails.Error;

                if (loginDetails.status_message == "Valid" && loginDetails.status_code == "1")
                {
                    ApplicationState.SetValue("EmailId", _userId);
                    ApplicationState.SetValue("UserID", loginDetails.userId);
                    ApplicationState.SetValue("SessionId", loginDetails.sessionId);
                    ApplicationState.SetValue("Password", _password);
                    httpClient.Dispose();
                    Frame.Navigate(typeof(Home));
                }
else
{}
catch(Exception e)
{}